My sister and I came in the evening, just in time to watch the sunset. The views were awesome. However, be warned, the rides are much scarier once you make it to the top. Hell, even the extra long elevator ride freaked me out!
I did conquer my fears and tried the "Big Shot". I thought it'd be much more intense, but it's just like any other drop ride. It just comes with a great view. Also, its only about 30 seconds of fun for $15. I would've settled for the $20 elevator ride and stopped there.
I'd say give the Stratosphere a try, at least once, during your Vegas visits. It's expensive for what it is, as everything is in Vegas, but it's fun and is something different.